The Intelligence System
General intelligence draws on connections between regions that integrate verbal, visuospatial, working memory, and executive processes. ~ German neurobiologist Jan Gläscher et al
Intelligence processing is distributed throughout the body. Numerous functions are autonomous. Nonetheless, mentation is greater than the sum of the physical parts when it comes to making sense of the world.
Organs and glands have some autonomy in meeting the needs they serve. Subconscious processes that alter under stress – such as heart rate and respiration – are regulated for readiness. The digestive system has its own intelligence system in accomplishing tasks essential to nutrient intake and distribution.
The peripheral nervous system is divided into the somatic nervous system and the autonomic nervous system. Whereas the somatic nervous system transmits voluntary impulses, the autonomic nervous system is the nerve network for internal functioning that is usual subconscious.
The autonomic nervous system acts as a communication network for internal organs and glands. Autonomic functions include respiration, cardiac control, vasomotor activity, and reflexes such as coughing, sneezing, swallowing, and vomiting. The autonomic nervous system interfaces with the hypothalamus in the brain.
These are 3 divisions of the autonomic nervous system: parasympathetic, sympathetic, and enteric. The parasympathetic nervous system is associated with glands and organs. The sympathetic nervous system facilitates homeostasis and helps prepare the fight-or-flight response. The enteric nervous system aids digestion.
The pancreas is a complex factory for producing hormones. The pancreas regulates blood sugar level and tissue metabolism. The pancreas is an intelligent monitor and regulator which affects the entire body.
The spinal cord is one of the body’s main communication networks, comprised of glia and their neurons. The spinal cord also has primal processing capability. Witnessing violence evokes a strong response in the spinal cord: prompting a quicker readiness than cognitive processing could give. Emotionally neutral or pleasant experiences barely register with the spinal cord.
The physical intelligence system is thoroughly integrated, with all cell types instrumental. Neurons provide raw data to glial cells for transformation into information. Besides acting as a signal conduit, neural pathways perform some pre-processing for glia, which manage the physiological correlates to memory and other mentation.
The Brain
General intelligence doesn’t depend on specific brain areas at all, and just has to do with how the whole brain functions. ~ American psychologist and neurobiologist Ralph Adolphs
When one exists, an animal’s brain harbors the control physiology for much of its body. The brain exerts centralized regulation over other body organs via nervous system conduction.
Prototype brain circuits originated very early and have been maintained across animal species throughout evolutionary time. There are deep similarities between our brains and those of insects. ~ English neurobiologist Frank Hirth
Though the brain acts as an entangled organ, there are processing loci within for certain functions. This provides an evolutionary advantage in being able to perform separate tasks simultaneously (parallel processing), such as autonomic functioning and various forms of mentation. For instance, the hypothalamus regulates the autonomic nervous system. During localized activity, other portions of the brain are actively contributing, albeit less intensely.
Many brain communications are chemical, not electrical (as well as always being energetic). Calcium waves play a key role in the physiological correlate to cognition and memory.
The brain acts on the body by driving chemical secretions and generating muscle activity patterns. Simple responses, such as reflexes, are mediated in the spinal cord or peripheral glia. More complex perception and behaviors involve the central brain.
All we ever observe is the concomitant variations or correlations between states of the brain and states of the mind. Correlation is not causation. ~ American physician Larry Dossey
The 10% Myth
Change your thoughts and you change your world. ~ Norman Vincent Peale
A popular myth – fabricated and perpetuated by American Christian preacher Norman Vincent Peale – is that humans employ only 10% of their brains. (This 10% myth assumes that the brain is responsible for mentation, which is itself a myth.) However happy the thought, it is a mathematical impossibility to apportion a percentage to routine brain activation. The grain of truth to this is that most people do not exercise sufficient self-control to discipline their minds or their lives to enjoy the abundant benefits that consciousness is capable of.
Anatomy
The brain’s importance to the body is emphasized by its physical protection. While capillaries in other parts of the body allow cells to absorb harmful substances from the blood, the brain has a blood-brain barrier: a filter that grants limited permeability.
Membranes in the brain’s blood vessels screen out many substances of questionable integrity. Pharmaceutical makers have been daunted in trying to deliver drugs past the blood-brain barrier.
Cerebrum
The largest, topmost layer of the brain is the cerebrum. The external layer of the cerebrum is the nerve-rich cerebral cortex which houses physical sensory processing. The term cortex simply means outer layer. While only 5 millimeters thick, this gray matter has 1/3rd of all the nerve cells in the human brain.
The cortex is a highly modular structure, with numerous specialized areas that communicate with each other through a distributed network of long-range connections. Processing requires routing neuronal activity across weakly-connected cortical regions. Signal strength across regions is maintained via synchronicity in spiking activity, which is furthered by coherent oscillations.
Oscillatory activity unleashes network resonance that amplifies feeble synchronous signals and promotes their propagation along weak connections (“communication through resonance”). The emergence of coherent oscillations is a natural consequence of synchronous activity propagation. ~ French neurobiologist Gerald Hahn et al
Astrocytes help maintain neural oscillations, and so regulate neural network connectivity.
Deeper with the brain, in the white matter, resides centers for voluntary motor control, learning, decision-making, cognitive and emotional functions. The nervy bustle about the cerebral cortex belies executive processing within.
The human cerebrum surrounds older evolutionary parts of the brain common to all vertebrates. The limbic, olfactory, and motor systems are networked via fibers to the brain stem and spinal cord.
Thalamus
The thalamus acts an information switchboard: relaying sensory and motor signals to the cerebral cortex. The thalamus regulates consciousness, alertness, and sleep. The thalamus primes the body for fight-or-flight response.
Cerebellum
The term cerebellum literally means “little brain.” It coordinates muscle activity and maintains bodily balance. Physical dexterity is a product of cerebellum activity.
Brainstem
The brainstem is the posterior part of the brain, adjoining and continuous with the spinal cord. The brainstem includes the midbrain, pons, and medulla.
The midbrain is a set of structures associated with alertness, the wake/sleep cycle, temperature regulation, motor control, and relaying vision and hearing signals.
The pons relays signals from the forebrain (cerebrum) to the cerebellum and medulla, as well as carrying sensory signals into the thalamus. The pons is active during dreaming.
The medulla is the lower half of the brainstem. The medulla concerns itself with nominally autonomic functions such as breathing, heart rate, blood pressure, and vomiting.
Gray & White Matter
The brain has 2 primary cell types, commonly characterized by their color. The color designation derives from appearance of a brain preserved in formaldehyde. In a working brain, white matter is pinkish white, while gray matter is pinkish tan. The pink hue comes from blood capillaries.
The outside of the brain is largely coated in nerve cells: gray matter. Inside are glia cells: white matter. Overall, glia cells predominate in the brain, both in brain mass and in processing control.
Hemispheres
Brain asymmetry enhances cognition. Directional biases of brain function are a putative adaptation to social behaviour. ~ Australian zoologist Lesley Rogers et al
Brain lateralization is ubiquitous in the animal kingdom. Honeybees have lateralized brains. Generally, the left side of the brain controls right-side body functions and vice versa.
The human cerebral cortex has 2 hemispheres: the left and right halves of the brain, connected by a tremendous number of pathways. The largest conduit connecting the left and right hemispheres is the corpus callosum, which facilitates interhemispheric communication via 200–250 million contralateral axonal connections.
The corpus callosum is the largest white matter (glial) structure in the human brain. Only placental mammals have a corpus callosum, though other animals have analogous fiber bundles for interhemispheric discourse.
Musicians that began learning their instruments before 7 years old have a larger corpus callosum than non-musicians, along with bulked-up auditory and motor areas of the brain.
Studying epilepsy, American neurobiologist Roger Sperry found that cutting the corpus collosum reduced seizures. The unsurprising side effect to this brain butchery was loss of mental integration. With a split brain, functions that predominately occur on one side of the cortex could no longer coordinate with the other.
In touching a recognizable object with the left hand without seeing it, a person with a severed corpus callosum would not be able to name it. Sensory-motor signals from the left hand are processed in the right hemisphere. Naming an object requires language processing, which is seated in the left hemisphere.
From such brain damage studies arose a left-brain/right-brain hypothesis: that the left hemisphere is rationally analytic, while the right hemisphere is emotive and creative. Despite the grain of truth in the brain processing input from the opposite side of the body, the left-brain/right-brain hypothesis overstates the situation.
Motor control, vision, and tactile brain processing for the left side of the body are handled on the right side of the brain, and conversely. The right side of the brain moves eyes to the left, while the left brain moves eyes to the right.
While vertical motion can be processed in one contralateral hemisphere, apparent horizontal movement requires integration between the hemispheres via the corpus callosum.
Individuals differ in the performance and quality of inter-hemisphere communication – more so than within a hemisphere. This affects subjective experience.
The left hemisphere handles routine behavior, while the right is responsible for unusual events and emergencies, along with associated intense emotions to provoke memory storage.
Foraging is a left-brain activity, while attacks are predominantly processed in the right hemisphere.
Small numbers are processed in the right side of the brain, while large numbers are handled in the left.
The right hemisphere is active in representing the space around the body and interacts with processes that maintain alertness of the environment. Resolving visual incongruities, language processing, and speech motor control stimulate the left hemisphere.
Language illustrates the importance of lateralization. Brains with weak lateralization struggle with literacy and language processing. In contrast, ideas and insight, rationalization of emotionally difficult decisions (emotional logic), appreciation of sound, and mental object manipulation invoke right hemisphere exertion.
Brain pathways that run longitudinally and laterally provide feedback mechanisms for behaviors. Speech generated largely via left hemisphere processing is regulated in other brain areas, including in the right hemisphere: especially emotive intonation.
Babies born without a corpus callosum – where the 2 brain hemispheres are separated – gain compensation by the brain growing alternate pathways which permit interhemispheric communication.
While certain localized areas correlate with certain functions, brain activity is entangled. Communications constantly course throughout the brain, operationally knitting it together.
Lobes
Besides hemispheric bifurcation, the human cerebral cortex is conventionally characterized as having 4 lobes: frontal, parietal, temporal, and occipital.
The frontal lobe contains most of the neurons in the brain that are sensitive to dopamine. For mammals, dopamine is associated with reward and its attendant functions: attention, motivation, learning and planning. Dopamine tends to selectively limit sensory input from the thalamus to the forebrain.
The temporal lobe is the region of the cerebral cortex in both hemispheres that is active when the mind is perceiving, processing emotions, and working with language.
The temporal lobe contains the hippocampus, which is active in shuffling information from short-term to long-term memory, modulated by the amygdala, which is energetic during emotional reactions.
The hippocampus and amygdala are generally considered part of the limbic system. The limbic system is a set of brain structures related to emotions. Memories are formed by emotional excitement, including motivation. Paul MacLean invented the limbic system in the 1940s, and the concept has become controversial: considered archaic by some, as it is based upon brain anatomical relations no longer accepted as accurate.
(The limbic system controversy highlights the artifice in modern brain science, with differentiation primarily based upon identifying localized areas of intense measured electrical activity during certain tasks, disregarding that less intense electrical jitters elsewhere may be as essential. Taking electrical measurements of brain activity has been the main source of misattribution in neurobiology: namely, attributing mentation to neurons while ignoring glia, which communicate with each other mainly through calcium-based energy waves. Further (and most saliently), the brain correlates with but is not causal to mental activity, thereby denigrating as significant the exercise of identifying localized functionality. Such assumptive miscomprehension led to tens of thousands of brain surgeries which caused more damage than good. Though research has been voluminous, the conventional matterist theories of neurobiology today are about as informed as Hippocratic humorism. This section on intelligence physiology is mostly trivia: more about matterist misinformation than meaningful information. The takeaway point is that physiology, like all of Nature, is stunningly intricate in presenting the ruse that physicality is reality.)
The parietal lobe is active while integrating sensory information from distinct stimulated sense organs (modalities). From this, the parietal lobe is linked with spatial orientation and thereby affords navigation. The parietal lobe is associated with a sense of physical self. In other words, the parietal lobe is active when considering objects in space.
The mammalian brain occipital lobe is lively during visual processing. From disparate tidbits of photonic input, the mind presents a view of the world while the occipital lobe is in a frenzy of electrochemical activity.
We can no longer view the brain as a bunch of specialized compartments that don’t interact much. ~ American psychologist Ladan Shams
Localization
Discoveries at the turn of the 19th century were the beginning of conceptual compartmentalization of cerebral functioning, starting with the 2 lobes of the cerebrum. This set the stage for the era of brain localization: identifying which parts of the brain handled different processes.
In the mid-19th century, French physiologist Pierre Flourens lobotomized pigeons and rabbits to investigate localization. He concluded that the cerebrum was responsible for higher mental functioning, the cerebellum handled balance and motor coordination, and the medulla nominally managed autonomic systems, including circulation and respiration.
Flourens also found that destroying the brainstem (medulla oblongata) resulted in certain death. He also showed that the brain could reorganize itself. In doing so, Flourens proved that strict localization could not be the correct impression of mental processing. Flourens failed to pinpoint specific regions for cognition and memory, leading him to believe that this processing was diffused.
Also in the mid-19th century, French anatomist Paul Broca was an early proponent of brain mapping, and a firm believer in strict localization. His mistaken belief arose after studying the brain of a man who lost the ability to speak after suffering from a brain lesion but could still understand speech.
With rare exception, in the 19th century, and for more than half of the 20th century, scientists believed that brain areas were so specialized that one area dedicated to sensory input processing could never do the work of another.
Extending the concept of the central and peripheral nervous systems being not only structurally but also functionally different, the senses were considered localized receptors, with each sense sending its signals to a specific part of the brain for processing.
Phrenology
The idea of brain localization led to phrenology, which was advocated by German physician Franz Joseph Gall in the late 18th century. Phrenology was very popular in the 19th century, influencing neurobiology and psychiatry.
The idea behind phrenology was that the brain is the organ of the mind, and that certain brain areas have specialized functions. In a word: localization.
Phrenologists believed that certain brain areas developed proportionally to a person’s propensities. Further, the cranial bone conformed to accommodate these different brain areas, with their corresponding character traits. As such, getting a sense of a person’s capacity for a given personality trait could be had by simply measuring the relative area of the cranium overlying a particular brain part.
The simple form of phrenology was feeling for bumps on the head. Phrenologists charted such personality attributes as caution, combativeness, hope, wit, and self-esteem to areas of the skull.
While mainstream academia was skeptical of phrenology from the get-go, phrenological inability to be a predictive indicator led to its dismissal as a pseudoscience in the early 20th century. One of the later-day proponents of phrenology was the Belgium Catholic priest Paul Bouts. But then, Christians ipso facto have shown themselves as gullible.
○○○
Whereas phrenology was discredited, the idea of localization firmed in the minds of brain scientists. In the 1950s Canadian neurosurgeon Wilder Penfield created brain maps to assist his surgeries. Penfield treated patients with severe epilepsy by destroying the brain cells where the seizures supposedly originated. To prepare for the treatment, Penfield created maps by stimulating the brain with electrical probes to observed responses, and so more accurately target the responsible brain areas, thus hoping to reduce side effects from the destructive surgery.
In 1952, Penfield wrote that stimulating the temporal lobe led to vivid memory recall. This tidbit was oversimplified in pop psychology publications under Freudian sway, including the 1969 best-selling bunkum I’m OK, You’re OK, by American psychiatrist Thomas Harris. The book falsely claimed that the brain records memories in perfect detail but such exactness is not available to the conscious mind.
Penfield found a topological relationship of brain to body. This idea was furthered by discovery that the frontal lobes seemingly housed the brain’s motor processor, initiating and coordinating muscle movement. The 3 lobes behind the frontal lobe – temporal, parietal, and occipital – comprise the brain’s sensory system: active while processing sensory information from the eyes, ears, skin, and other organs.
In his brain mapping Penfield also hoped to a scientific basis for the existence of the human soul. Instead, his work only led other neurobiologists astray. Penfield did not find the soul embedded in neurons.
Because scientists believed that the brain had a fixed structure, and processing was localized, they assumed, and were taught, that the maps were immutable, and universal: the same brain map applied to every human. Very tidy but quite untrue.
Lobotomy
An upshot to localization as gospel was the surgical practice of lobotomy: destroying parts of the brain to relieve brain-related and mental disorders.
Swiss psychiatrist Gottlieb Burckhardt made forays into clinical brain damage in the 1890s, claiming a 50% success rate, but his colleagues gave scant credibility to his crudeness and lack of post-operative verification. One said that Burckhardt suggested that “restless patients could be pacified by scratching away the cerebral cortex.”
Lobotomies had their heyday in the 1930s to 1950s, used to “treat” a wide variety of disorders, including “moodiness” and “youthful defiance.” Often a patient’s informed consent was not obtained before the butchery.
A practice grounded in scientific ignorance meant that the results were often tragic. The Soviets were relatively quick to catch on. The USSR banned lobotomy in 1950, concluding the procedure “contrary to the principles of humanity,” noting that it turned “an insane person into an idiot.”
While concerns have been aired, lobotomies are still legal, and occasionally practiced, in the United States, Britain, and other Western countries. Lobotomy has been practiced the most in the US, with around 40,000 victims.
Plasticity
The same areas of the brain active while recognizing faces are similarly astir during recognition of different models of cars and trucks. The pattern matching of categorization is a primary mental activity, irrespective of what it is classifying.
Mental skills a matter of memory and of forgetting. Bad habits can be difficult to unlearn. Repeated activation of brain areas involved in the exercise of habits acts as physiological reinforcement. Hence the cruciality of discipline in developing and maintaining healthy habits.
We are what we repeatedly do. Excellence, then, is not an act but a habit. ~ American historian Will Durant
The mind-brain is capable of adaptation throughout life, especially so during the early, formative years.
Brain areas and connections are allocated to skills that are practiced. What has been learned may be lost with disuse. As life progresses, brain plasticity is a discipline: use it or lose it. The brain is literally the muscle of mentality: able to adapt and grow with proper nourishment and exercise.
Brain power improves by brain use, just as our bodily strength grows with exercise. ~ English writer A.N. Wilson
Autopsies have shown that educated animals have more neural branches. This increase in branches drives neurons farther apart, giving the brain body by greater volume and thickness.
Deficiency or change in one brain module cascades to functional and structural changes in other brain modules. The brain adapts: becoming more acute to compensate for a deficiency elsewhere. By blindfolding people, German neurologist Alvaro Pascual-Leone demonstrated that the occipital lobe, which normally processes vision, could alternately process sound and touch.
American neurobiologist Michael Merzenich investigated “false localization” in the 1980s. When a large peripheral nerve bundle is cut, wires can get crossed during nerve regeneration, as axons reattach in a different pattern than before the injury. When this happens while healing a person may experience sensory dislocation. A cut in the arm can result in the thumb feeling touched when it was actually the index finger. This can last for months. As nominal brain mapping is geographically oriented, this phenomenon makes sense from a localization perspective: that the brain map corresponds to a point-to-point model.
What Merzenich discovered by mutilating monkeys was that the nervous system heals in time by straightening the crossed signals. Merzenich observed that the topological brain maps of the healed monkeys were in a slightly different location than before the injury.
If the brain can remap and normalize after injury, the idea that the brain is hardwired must be wrong. Brain processing must be plastic.
The brain is plastic in at least 4 known ways: the number of neurons, the network connections between neurons, the way in which neurons massage signals, and the speed at which signal processing occurs. The physical adjunct of learning is a process that often involves changes in all ways: new cells grow, processing patterns change, the network of circuits connecting modules are altered, such that changes in one area of the brain flows to another, and, with rote practice, the speed of processing increases.
Diverse kinds of sensory energy stimulate receptors, such as the skin sensing vibration, moisture, pressure, or temperature; light beaming the retina; and vibrations onto hairs deep in the ears. These sense receptors translate various input types into signals carried by nerve cells, which employ a combination of electrical and chemical energy to transmit data bits to the mind-brain. Glia cells in the brain are busy as the bits are collated and analyzed. The mind-brain works by memory-based pattern matching, filling in gaps as necessary. This is the nature of optical illusions.
Much of the mind-brain appears polysensory: able to process incoming data patterns from more than 1 source. These patterns are the universal language of the mind-brain.
There are no visuals, no sounds, et cetera, moving through the neural network to the brain. This is a definitive indication that the brain is merely a cohort to the mind, as a purely physiological explanation of sensation is impossible.
Areas of the brain are interconnected plastic processors, capable of handling a variety of inputs from multiple sources. A blind man probing with a cane causes repeated vibrations in his hand, which transmit signals to his brain, allowing a pattern in the mind-brain to emerge from sensed obstacle points where the cane touched something. The mind-brain patterns tactile points together geographically based upon the angles of the hand and wrists corresponding to the timing of touches. Different senses of skin pressure and muscular exertion are coupled together in the mind-brain as a patterned signal. These multiple patterns from different sensory complexes are processed in the portion of the brain used by sighted people for vision.
Like echolocation, the cane acts as eyes. Cane taps are like photons on the retina: crude pictures by comparison, but sight nonetheless. American neurobiologist Paul Bach-y-Rita understood that “we see with our brains, not with our eyes.”
American neurobiologist Vernon Mountcastle discovered that the human cerebral cortex comprises a 6-layer processing structure, referred to as a cortical column. Dolphins have a 5-layered cortical column, while reptiles have 3 layers.
The visual, auditory, and sensory cortices all use the same processing structure. Such consistency makes perfect sense from an evolutionary viewpoint, where modular similarity is a norm.
Processing in the sensory cortex is plastic and adaptable. The cerebral cortex, the thin outer layer of the brain, if kept active, selectively refines its processing capacities to fit each task at hand.
As new material is learned, network connections become more efficient in stages. First, brain maps enlarge to accommodate mastering the subject or task at hand. With practice, though the same number of glial cells may conduct, fewer neurons are needed to perform the task. Maps become more precise. Discrimination is enhanced.
Further, as the learning is reinforced, processing speeds up: which means that the speed of thought is plastic. Reaction time is more than reflex, as any sports player can tell you: it is the mind-brain in action.
Speed of thought is a critical component of intelligence. The more quickly processing transpires, the more information that can be absorbed and considered in decision-making.
Besides sheer speed, training results in more defined intelligence cell connections and greater synchrony. This give clearer, more powerful signals. The physiological signal-to-noise ratio of thought goes up.
One limiter always remains. The quality of memory is only as good as an individual’s perceptiveness.
Learning itself is not casual. Instead, paying close attention is essential to effecting long-term plastic improvement.
Acetylcholine – a neurotransmitter necessary for learning – flows freer the more difficult the learning. Dopamine – the brain’s reward chemical – plays a role consolidating memories. Acetylcholine sharpens while dopamine reinforces.
Strokes
Areas of a brain can be irreparably harmed in a variety of ways. One of the more devastating is a stroke. A stroke causes a loss of brain function due to disrupted blood supply to the brain. Often the neurological damage is permanent: part of the brain dies.
American psychologist Shepherd Franz was interested in brain functioning. By 1915 Franz had demonstrated that patients paralyzed by strokes, some for as long as 20 years, could partly recover functionality with the aid of brain-stimulating exercises. The exercises were aimed at gradually restructuring the brain.
Memory
Memories are physically stored holographically. A holograph (aka hologram) is a recording made by retaining interference patterns: the superposition of energetic waves.
Storage and retrieval of memories involves synchrony across different brain regions. This owes to the nature of memory as entangled by associations, which is a capability facilitated by holography.
One property of holograms is that information retention is distributed. Whereas snippets of photographs only show a fraction of an image, bits of holographs retain the entire picture.
Holography explains how brains can story so many memories in such a small volume. Hungarian-American polymath John von Neuman calculated that a person stores 280 trillion memories in a lifetime. Such information capacity can only be achieved via holography.
Penfield’s assumption of memory localization, based upon stimulating select brain areas, was belied by American psychologist and behaviorist Karl Lashley demonstrating that memories are in fact distributed throughout the brain.
There is no demonstrable localization of a memory trace. ~ Karl Lashley
Evolution
As with all other parts, the human brain is a product of evolutionary descent. As such, its features are found in all other mammals, albeit in different proportions and durations of development. The basic structures of the brain date back much further: before animals lived on land.
The functions of all animal mind-brains are essentially the same: perceive the environment and formulate activities for survival and enjoyment of life. The differences between brains – whether fish, fowl, or fellow – are adaptations to lifestyle.
To coordinate movement and gauge water pressure, fish have a large cerebellum. Befitting a near descendant, the amphibian brain resembles that of a fish except for structures adapted to life on land. These include adaptations allowing better senses of smell, hearing, and vision, as well as coping with gravity: a larger olfactory bulb, larger forebrain, and midbrain changes.
The reptile brain evolved from its amphibian antecedent with a more sophisticated olfactory processor, better adapted to the a more arid environment. Birds are a reptilian offshoot. Hence their olfactory bulb is relatively large, though avian sense of smell, with exceptions (e.g., kiwi), is unexceptional.
The avian cerebellum is well developed to control balance and position in flight. Bird cerebrums are larger; perhaps related to their greater sociality compared to reptiles.
Mammals do not face the agility demands of bird flight, so their cerebellum is overshadowed in size by the cerebrum, which is also more elaborated.
The cerebrum surface (cortex) of reptiles and birds is relatively smooth, as it is for rodents. With descent, primates show progressively larger cerebrums relative to body size. Apes have larger cerebrums and more wrinkly cortices than monkeys.
With neural growth guided by glia, cortex creases arise naturally due to mechanical instability in soft tissue that grows unevenly. Cortex folds afford greater operational volume for the same size. (Similarly, the stacked sheets of the endoplasmic reticulum, a eukaryotic cell organelle, maximize production space within a limited volume.) The folds form ridges (gyri) separated by grooves (sulci).
The mammalian cerebral cortex underlies many higher-order processes, such as perception, memory, language, and advanced motor skills. With its intricate furrows and ridges (i.e., the sulci and gyri), the complexity of the cerebral cortex is evident even at its surface. Beneath the surface, the cerebral cortex is separated into layers of densely packed neurons with axons reaching deep into the white matter. These layers are divided further into functional regions that correspond to the body plan. ~ developmental neurobiologists Lora Sweeney & Liqun Luo
Marine ragworms first appeared well over 500 million years ago. Their mushroom-body brains share many features with the mammalian cerebral cortex. While considerably different in numerous particulars, the genetic bases for development of the ragworm mushroom-body and mammalian cerebral cortex are analogous.
Executive System
Goal-directed behaviour is regulated by a large collection of interconnected brain regions. ~ Canadian behavioral neurobiologist Jonathan Britt
The term executive system is an umbrella term used by psychologists to encapsulate the mind-brain processes involved in cognitive flexibility, problem-solving, decisions, planning, rule acquisition and application, and abstract thinking. The physical wattage of the executive system resides in glia cells. This includes memory and what much of mentation consists of: pattern construction and matching.
Glia
Glia are the conductors. ~ American neurobiologist Douglas Fields
The brain has a predominant cell type: glia. Neurons account for only 15% of human brain cells. 85% are glia.
German doctor and biologist Rudolf Virchow observed glia cells through a microscope in 1858. To him, they looked like “nerve putty.” Hence, the cells of intelligence were relegated by Virchow to the Greek for “glue”: glia. German pathologist Carl Weigert furthered Virchow’s original 1858 “glue” observation, proposing that glia were structural scaffolding for nerve cells.
One of Virchow’s brilliant students, German physiologist Carl Ludwig, went against his mentor in proposing that glia and neurons signaled each other. Ludwig believed that brain functions were accomplished by an interconnected, interactive, neuronal-glial network.
A skilled illustrator and cogent writer, Spanish neurologist Santiago Ramón y Cajal elucidated and fiercely defended in the late 19th century what became known as the neuron doctrine: neurons were the cells of intelligence.
Astrocytes are a major type of glia cell. Based upon dye studies showing astrocyte connectivity, Italian physician and pathologist Camillo Golgi considered glia cells significant, though secondary, in mentation.
Golgi was a contemporaneous rival to neuron supremacist Cajal. The two men shared the 1906 Nobel prize in physiology and medicine.
Despite Golgi’s findings, which brought attention to the role of glia in the brain, Cajal’s simpler and thoroughly neuron-centric influence prevailed in scientific circles. Cajal is credited as the father of modern neurobiology, the mainstream brain ‘science’ religion.
Cajal observed that aging resulted in fewer synapses. From this he bizarrely proposed that neural synapses strengthen from learning. This wrong-headed notion resulted in generations of researchers ardently, but unsuccessfully, striving to prove it. The cloistered world of neurobiology diligently pursued blind alleys rather than question unfounded presumptions. Because of Cajal and his disciples, glia went unstudied for 6 decades.
Glia are still generally considered brain stuffing by neurobiologists, largely filling void space, performing some housekeeping functions for the nerve cells that are considered the center of thought.
The evidence is building up that we can explain everything interesting about the mind in terms of interactions of neurons. ~ Canadian cognition philosopher Paul Thagard in 2015
Into this century neurons are regularly credited with the accomplishments of glia. Nerve cell transitions were studied while astrocytes were studiously ignored. Only in the 2nd decade of the 21st century has this begin to change.
Misattribution is easily had by carelessly mistaking effect for cause. One cannot see what is not looked at, or looked askew via a predetermined perspective. In academic disciplines, only economics has proceeded with as much built-in bias as neurobiology: a shameless disgrace to science.
◊ ◊ ◊
Neurons are utterly dependent on glia to fire their electrical impulses. ~ Douglas Fields
Neurobiologists long assumed that neurons were the governors of consciousness, particularly the transition between sleep and the awake state. Instead, that physiological transition occurs through ion flows regulated by glia.
Once dismissed as mere packing material, glia make up 85% of the cells in our brain, and are now known to control many of the brain’s functions. Astrocytes ferry nutrients and waste and mediate neuronal communication. Oligodendrocytes coat axons with insulating myelin, boosting signal speeds. Microglia fight Infection and promote repair; when they fail, so does the brain. ~ Douglas Fields
Hunger is monitored and its response physiologically controlled by glia, not neurons. This is done by regulating the release of the hormones leptin and ghrelin, which control the sensation of hunger and adjust energy expenditure. The effects of leptin and ghrelin on metabolism come by commanding neural circuits.
Neural activity patterns do not correlate with those of mentation. After extensive study of nerve cells for well over a century, neurobiologists still cannot explain memory via neurons.
By regulating the synapses, glia control the transfer of information between neurons. ~ Italian neurobiologist Maurizio De Pittà
Via ionic calcium waves, glia signal each other in a way that indicates information storage. Neurons have no memory capacity beyond that of other soma cell types. That’s because the physical correlate of mentation transpires in glia, not nerves.
In the brain, astrocytes control how many new neurons are formed from neural stem cells and survive to integrate into the existing neuronal networks. Astrocytes do this by secreting specific molecules, but also by much less understood direct cell-cell interactions with stem cells. ~ Swedish neurobiologist Milos Pekny
Glia guide developing neurons, form myelin, sop up chemicals used in cell-to-cell communication, manage brain washing during sleep for its rejuvenating effect, and generally contribute to the health and well-being of nerve cells and their environment. And glia do much more. Glia are the adult stem cells in the brain: able to reproduce themselves, and neurons if need be. Glia regenerate and grow locally to store more information.
Evolutionary Perspective
Vision is one of the key factors in triggering evolutionary changes. ~ German zoologist Brigitte Schoenemann et al
An evolutionary perspective highlights the importance of glia. If glia function as the physical correlate to the mental library, then species with greater cognitive facility should have proportionally more glia; and so it is. A leech has 1 glial cell for every 30 neurons. The widely researched earthworm has 1 glia for about every 6 neurons. Glia comprise 16% of a worm’s nervous system cells. Vinegar flies: 20%. Rodents, such as mice and rats: 60%. Chimpanzees: 80%. Humans: 90%. The ratio of glia to neurons increases with what is broadly considered cognitive capacity.
Not only does the ratio of glia grow, but so does their size. Astroglia in humans have 27 times the volume of mouse astrocytes.
Complex behavior in both invertebrates and vertebrates increases along with the compartmentalization of neurons by glia. Glia organize insect brain areas. Glia comprise 57% of bee retina cells. The more processing required for functioning, the greater the glia.
Coleoid cephalopods – octopi, cuttlefish, and squid – are the most intelligent invertebrates, and have the most complex invertebrate intelligence system. Astrocyte-like cells predominate in their large brains.
Coleoids contemplate stimulus, demonstrated by selectively changing skin coloring in response. They make thoughtful decisions based on vision and touch.
Coleoids express emotive behavior in how to handle stressful situations, deciding whether to run or fight. They have complex courtship behaviors. Coleoids are social: when isolated from their own they shoal with fish.
Invertebrates don’t seem to need to sleep. Sleep first appeared with fish.
Fish have less behavioral variation and sophistication than coleoids. They also have fewer glia.
Amphibians exhibit a form of sleep. They are not as behaviorally complex as some of the brighter fish species, but they do learn spatially and develop specific techniques for nabbing prey. Amphibians also have more astrocytes than fish.
Though of a distinctive design, avian brain differentiation approaches that of mammals. Birds are highly skilled manipulators of spatial information.
Birds see color in a different way from humans. ~ Swedish zoological ecologist Anders Ödeen
Birds visually process and categorize colors the same way that humans do, even though their color vision is distinctive, with 4 color receptors compared to 3 in humans.
Birds are also prodigies of temporal processing. Songbirds learn new songs. Some create sonic productions worthy of the finest human composers. Birds raised in isolation develop less elaborate songs. As with other gregarious animals, bird brains need conspecific stimulation to achieve their potential.
Songbirds develop signature songs by which they are recognized as individuals by others. Birds are natural tool users. Bird’s nests, which are often surprisingly complex, are exemplary.
Cortical folding increases with later-evolved species, such as cats, dolphins, and primates. Humans have 35% more cortex glial cells than chimpanzees.
◊ ◊ ◊
Glia are at the hub of brain health and disease. ~ Douglas Fields
The state of someone’s glia, including the genes used to produce them, is so consistent through the years that it can be used to predict someone’s age. The same cannot be said of neurons.
Brain Malady
A long-known fact is that brain tumors are almost always of glia cells. These tumors would not be so devastating if neurons were running the show.
Cognitive diseases – such as autism, epilepsy, Alzheimer’s, and Parkinson’s – occur from defective glia, not neurons.
In all degenerative brain diseases, the first symptom, even before the loss of mental faculty, is loss of a sense of smell. Smell receptor cells actively lock onto ambient molecules for detection, requiring frequent replacement of these receptors. Hence, sense of smell is constantly changing, and an apt indicator of holistic health.
The olfactory bulb has the highest turnover of cells in the brain. Glia are the stem cells for this turnover.
Glia manage the cleaning network in the brain: the glymphatic system. Guided by glia, cerebrospinal fluid flushes out metabolic debris. The glymphatic system is especially active during sleep: whence the rejuvenation of repose. Chronic lack of sleep is an influential factor in developing Alzheimer’s: glia getting shortchanged in their housekeeping duties. Meanwhile, like blaming the potholes as the reason a road is bad, neurologists focus their research into Alzheimer’s on the proteins that aggregate in neurons; a byproduct of the disease, not the cause.
Seizures are generally attributed to out-of-sync overexcited neurons. But the cause is glial cells with out-of-control calcium exchanges.
Almost all brain research is focused on neurons to the exclusion of glia. Only occasional articles express surprise at discovering that white matter matters.
Down’s Syndrome
Down’s syndrome is a developmental disorder caused by trisomy of human chromosome 21 (HSA21), and is characterized by intellectual disability, epilepsy, and early onset alzheimer’s disease. ~Chinese molecular biochemist Wenbin Deng et al
Researchers who discovered that glia were responsible for the cognitive limitations associated with Down’s syndrome could not bring themselves to adjust their paradigm away from “neurons rule,” even as they confessed facts that glia, not nerve cells, run the show. The cognitive dissonance in their statements is startling.
Numerous studies have shown that astrocytes promote neurogenesis and synaptogenesis in neurons. Astrocytes exert profound effects on neuronal development as they provide support for neuronal survival, axon and dendrite outgrowth, and synaptogenesis. Such effects are largely mediated by a variety of factors that are expressed in and released by astrocytes.
Astroglial function is increasingly recognized as a critical factor in neuronal dysfunction in the brain. ~ Wenbin Deng
Development
Human embryos form a network of neurons from radial glial cells, which are stem cells. Radial glia appear in the 7th week of gestation, as the embryotic brain sprouts and grows.
Cell division creates a neuron connected to its glial mother cell. Initial transmitter expression in the womb is calcium dependent.
After a neural net is properly placed throughout the body, the final trimester of pregnancy furthers hooks up the neural connections to the brain. Astrocytes grow and fill niches near support neurons.
Astrocyte proliferation coincides with birth. Radial glia stop their neural network from creating divisions and turn themselves into astrocytes.
The explosive growth of the human brain in the 1st year after birth owes to astrocyte propagation. Meantime, nerve cell growth is fractional.
Humans begin to experience dreams and can retain long-term memories by around age 4, after glia grow and establish themselves postnatally. If neurons held memories, humans could recall being in the womb.
Nerve cells predominate in the cortex, which is gray matter. Cortex development increases to about age 8, then the brain becomes more streamlined. An adult cortex is considerably smaller than that of an 8-year-old.
Learning results in a temporary increase in neurons in the affected area. But as the learning takes hold and becomes rote, the neural pathways streamline: neurons atrophy and lessen in number. Meanwhile, more glia grow and remain robust with learning.
The cortex thinning that occurs from childhood is mostly apoptotic neuron loss, as streamlining of neuron-astrocyte synaptic contacts.
Impairments that we see in autism seem to be partly due to different parts of the brain talking too much to each other. You need to lose connections in order to develop a fine-tuned system of brain networks, because if all parts of the brain talk to all parts of the brain, all you get is noise. ~ neurobiologist Ralph-Axel Müller
Autism arises with a failure to prune neurons.
More is not better when it comes to synapses, for sure, and pruning is absolutely essential. ~ American molecular biologist Lisa Boulanger
Smarter children experience accelerated neural thinning. What neurobiologists believed to be neuronal plasticity is actually glial growth and signaling refinement via nerve cell pruning.
Glia Cell Types
There are several glial cell types: astrocytes, microglia, Müller, Schwann, and oligodendrocytes, among others. Each have their own tasks and function differently than neurons.
Glia have historically been categorized by their association with neurons. It has not been a rational taxonomy.
German anatomist Henrich Müller described retinal glia cells in 1851. Müller cells funnel light to green and red color (cone) receptors, increasing light absorption 10 times. Blue light is shuttled to rod cells, enabling night vision. Müller cells communicate with one another within the retina and modulate signaling out of the retina to the brain.
German physiologist Theodore Schwann, one of Müller’s pupils, discovered glia cells in the peripheral nervous system. Schwann cells reside in the myelin sheath coating the axon of neurons. Schwann cells speed nerve signals and help control muscle contractions though a feedback mechanism.
Oligodendrocytes
Oligodendrocytes are somewhat similar to Schwann cells in being in the myelin of axons. Whereas Schwann cells are part of the peripheral nervous stem, oligodendrocytes are in the central nervous system.
Oligodendrocytes are smaller than Schwann cells. Oligodendrocytes are abundant in the cortex astrocyte mass, which is the white matter of the brain. Rather than affecting brain chemicals, oligodendrocytes influence neuronal signaling rhythms via their presence in myelin.
The brain churns out new oligodendrocytes while learning new skills. These newcomers wrap extra myelin around the axons of neuronal circuits under construction.
Conversely, unused neural circuits wither because oligodendrocytes ignore them. The brain rewires itself based upon glial activity.
Myelin accelerates the transmission of electrical signals along axons. A signal takes 30 milliseconds to cross the brain on myelinated axons; 10 times faster than on un-myelinated axons.
Information processing relies upon signal synchrony, which delays disrupt. Modest additional thickness of myelin layers on axons tweak the timing of the brain’s electrical signals enough to bolster learning and memory.
Multiple sclerosis is a debilitating inflammatory disease in which myelin is damaged: disrupting nervous system communication, which results in a wide range of physical and mental disabilities. The cause of the disease is destruction of the glia that provide myelin sheath production.
○○○
Microglia are the smallest glia cell. They are the brain’s first responders to nervous system injury and disease: going on-site to coordinate damage clearance and direct reconstruction. Microglia also regulate synaptic connection quality in neurons. In early development, microglia guide nerve wiring connection.
Microglia monitor synaptic function and are involved in synapse maturation or elimination. ~ Italian molecular biologist Rosa Paolicelli et al
The ventricular system comprises 4 cavity structures in the brain – the ventricles – filled with cerebrospinal fluid. The ventricular system is continuous with the central canal of the spinal cord. The ventricles are interconnected.
Cerebrospinal fluid is a clear fluid found in the brain and spine that cushions and helps regulate cerebral blood flow.
Ependymocytes and tanycytes reside in the brain’s ventricular system. Among other tasks they perform defensive functions: coordinating response with the immune system to protect the brain from infection.
Ependymocytes line the spinal cord and the ventricular system of the brain. They regulate creation and circulation of cerebrospinal fluid.
Tanycytes are specialized ependymal cells that provide communication between cerebrospinal fluid and the central nervous system.
Astrocytes
The historical notion that astrocytes are cushions for the neurons to feel comfortable or protected is not the case. ~ Hungarian neurobiologist Tamas Horvath
Astrocytes were first described by German neuroanatomist Otto Deiters in an 1850s unfinished manuscript.
This star-shaped cell was named astrocyte in 1891 by Hungarian anatomist Mihály Lenhossek. Neuroglia was the vogue catchall term for non-neuron brain cells in the 19th century.
Astrocytes were previously called spider cells. Lenhossek thought all the glia should be lumped together as spongicytes and then further divided, one cell type being the astrocyte.
Neurobiologists long ignored the physical keeper of intelligence. This is a typical textbook description: “astrocytes are small cells involved in forming a structural and functional barrier between the blood and the brain.”
Astrocytes are the most abundant cell in the human cortex. There 4 times as many astrocytes in the human brain as there are neurons. Astrocytes also line the spinal cord.
The center of physiological intelligence processing lies in the astrocytes. Astrocytes are the knowledge workers in the city of smarts reached by neuronal highways.
Early work in exploring the intelligence system relied upon measuring electrical impulses for localizing brain functions. As neurons are electrical conduits, the facile conclusion was to hold those cells responsible for thought.
Positron emission tomography (PET) scans are used to look at organ functioning. PET scans show that the areas of the brain that Penfield identified as responsible for mentation have increased blood flow. For example, speaking flushes the left temporal cortex with blood. Astrocytes, not neurons, have their end feet on blood vessels.
The brain is a voracious energy consumer: requiring 10 times more oxygen and nutrients than other organs. The dense network of brain blood vessels are set up by radial glia cells early in life. Radial glia cells are stem cell progenitors to astrocytes, oligodendrocytes, and neurons.
Astrocytes drive the master clock in the brain. ~ neurobiologist Marco Brancaccio et al
Astrocytes manage the brain blood supply, nourishing neurons with both oxygen and energy. They break down glucose from capillaries into lactate, which nerve cells can absorb for energy consumption within their mitochondria. Astrocytes maintain a glucose energy reserve for their neurons, for use when the metabolic rate of neurons in the area surges owing to increased inter-astrocyte communication demand.
Sleep is necessary for memory retention, by affording glial calcium wave processing and regeneration without external stimulus.
Astrocytes play pivotal, sleep-dependent roles in ‘cleaning the brain’ during sleep. ~ American neurobiologist Philip Haydon
Astrocytes nestle some of their pointed projections against neurons, determining how nerve cells connect.
Astrocytes, the most abundant cells in the central nervous system, promote synapse formation and help to refine neural connectivity. ~ American cytologist Anna Molofsky et al
Just as they are instrumental in nerve cell generation, astrocytes regulate the replacement of aged neurons.
Astrocytes are self-sufficient, self-signaling, and self-replicating. Neurons have no reason to exist except to support astrocytes.
Mature neurons do not function alone, whereas mature astrocytes often function without neural input. In a petri dish, neurons quickly expire without astrocytes, while astrocytes survive just fine.
Sensory input is transmitted by neurons to astrocytes, which process the data and signal appropriate motor action that is communicated by neurons. Simple reflexes bypass astrocyte processing, having been hardwired via prior astrocyte programming of neurons.
Astrocytes are the physiological form for thought processing, including pattern matching, memory recall and storage. Any and all decisions involve astrocyte activity.
In studying the effects of cannabis in the brain, researchers discovered the cells most affected in getting stoned.
The starting point for this phenomenon – the effect of marijuana on working memory – is the astroglial cells. Astrocytes modulate working memory. ~ Chinese neurobiologist Xia Zhang
From neuron to astrocyte, neurotransmitters get their message across, then a transmitter is absorbed by the astrocyte, broken down, and resynthesized for reuse. This happens with all transmitters: glutamate, dopamine, serotonin, and so on.
Astrocyte receptors at a neural synapse match the neuron’s transmitter use. In the cortex, that is frequently glutamate. In the basal ganglia, dopamine predominates.
At gap junctions where astrocytes interconnect, astrocytes selectively employ transmitters, though the functions of these channel releases are not yet understood. Astrocyte employment of transmitters differs somewhat from neuron use.
Astrocytes rule the cortex: controlling nourishment from the blood, releasing transmitters at a synapse to control neuronal firing, and dictating the type of signaling that a neuron is to perform. Neurons can fire at different frequencies. Astrocytes tend to invoke short signaling, suppressing long signals at the synapse.
Astrocytes receive signals from quick response messenger neurons, processing the input data into information, and selectively storing the result as memory. In turn, astrocytes stimulate neurons to send information elsewhere, and invoke muscular action.
Glia cells also affect neuron release of vasopressin and oxytocin: hormones that regulate whole body fluid balance, among other things.
Astrocytes maintain synapses: strengthening their connection through transmitter use and growth factors. Without astrocyte maintenance, neurons are stunted and produce few connections. Glia can also eliminate synapses. In short, neurons serve astrocytes, not the other way around.
Astrocyte growth can be a lifelong process. In the lower areas of the brain, such as the olfactory bulb and hippocampus, astrocytes readily regenerate and sprout – some turning into neurons to provide a fast link to cortical astrocyte centers where new knowledge nuggets can be processed and stored.
◊ ◊ ◊
The cognitive facilities of humans owe in part to astrocyte evolution.
Astrocytic complexity has permitted the increased functional competence of the adult human brain. ~ American neurobiologist Nancy Ann Oberheim et al
Human astrocytes are 2.6 times longer than those in mice. They carry calcium ion waves through the brain 5 times faster. Humans also have astrocyte subtypes which mice lack.
In one experiment, human glial progenitor cells were placed into mouse brains, where they multiplied and matured into astrocytes. Over several months, the introduced human astrocytes started to replace mice astrocytes. As the human astrocytes took over, the level of calcium signals in the brain increased 3-fold.
Mice with human astrocytes had enhanced neural communication. When tested on a battery of learning and memory tasks, the mice with human glial cells outperformed their mouse-brained counterparts.
◊ ◊ ◊
The hippocampus is the brain area especially active when forming new memories. ~80% of large neural synapses in the hippocampus are surrounded by astrocytes. Astrocytes physiologically store memories – not neurons, as commonly supposed.
○○○
Neural activity resembles a communication conduit: electrical signals flowing down axons to a chemical juncture, where a neuron either fires off a signal to neighbors or doesn’t. Glia are more complex: communicating through connected subnets of cells via calcium ion waves. Glia signal nerve cells and receive neural input. Glial waves correspond with the rhythmic pulses that constitute the physiological semblance of awareness.
Calcium Waves
Propagating waves of calcium suggest that networks of astrocytes constitute a long-range signaling system within the brain. ~ American neurobiologist Ann Cornell-Bell et al
Like sodium and potassium, calcium is a prevalent oceanic ion. All 3 chemicals had critical roles in the origination of life.
Calcium is essential for an organism to be multicellular. Cell interaction and division are calcium dependent. Calcium is the 5th most abundant element in Earth’s crust, and in the human body.
Stabilized calcium serves as a base material for bones. But it is the reactive nature of calcium that makes it especially prized for biological application. Calcium highly reacts with the organically significant elements nitrogen and oxygen, as well as spontaneously reacting with water.
The universe is fundamentally comprised of coherent energy waves. Apprehending and using information are also wave functions.
Calcium waves are the standard biological means for intelligence processing. Calcium signaling facilitated intercellular cell communication in early multicellular organisms.
Plants employ calcium waves for their rapid long-distance communication network. Root-to-shoot communiqués travel this way. Plant root growth depends on calcium. Flowers bloom based upon calcium signaling.
The significance of sodium and potassium in nerve cell transmission was long known. It was not until 1883 that English clinician and pharmacologist Sydney Ringer discovered, via frog dissection, the significance of calcium in neural communication.
Calcium is a cellular regulator in all bodily organs and is critical to proper development in both plants and animals.
When an egg is fertilized, the ovum initiates conception via a calcium wave. Mother’s milk is calcium rich.
Almost all cortical astrocytes are interconnected. The end feet of different astrocytes wrap around each other, forming junctions through which receptors bind cells. Gap junctions are fused together via intercellular channels.
About 230 gap junctions connect a pair of astrocytes in the brain. The control of myelination that facilitates neural conductance occurs via gap junctions between astrocytes and oligodendrocytes. Gap junctions are employed between neurons and astrocytes during nerve cell construction. Other organs also employ gap junctions, including the liver and heart. All such gaps are bridged by calcium waves.
Neurotransmitters stimulate astrocytes to produce a calcium influx, transmitted as a calcium puff: a calcium-based wave to other networked astrocytes. Calcium is the cell regulator of neural communication: necessary at nerve cell synapses to release transmitters.
Neural signals come in from the senses. If the strength of the neural firing is over a threshold, astrocyte calcium waves propagate to other astrocytes at frequencies harmonious to the firing of the neuron.
There is a feedback dynamic to sensory processing. Strong neural firing at the synapse is indicative of a strong sensory stimulus. Strong firing increases the capacity of an axon to fire. Astrocyte calcium waves become more frequent, and are more readily initiated, from previous strong neural signaling.
Glutamate level corresponds with glial activity. A shot of glutamate is released from an astrocyte as part of a calcium wave firing. An increase in glutamate release corresponds with an increase in calcium wave propagation.
Astrocytes don’t just signal neurons at their synapse. An astrocyte can signal a neuron anywhere along its body. As a calcium wave spreads, glutamate release stimulates more neurons.
Calcium waves affect astrocytes within milliseconds. This is relatively slow compared to neural electrical signal transmission, but that extra duration is essential. Calcium waves spreading more slowly than neuronal communication allows time to integrate and process information.
Besides inter-glial communication by calcium wave, calcium also acts on astrocyte genes and proteins: affecting long-term changes in an astrocyte’s reaction to calcium stimulus. This suggests memory storage.
○○○
Not only are astrocytes the cells correspondent with thoughts and memories, they also regulate hormone levels. Astrocytes produce proteins in various parts of the brain that regulate water homeostasis and microcirculation. These include brain angiotensinogen, atrial natriuretic peptide, and vasoactive intestinal peptide, all of which influence neurons that release hormones.
Regulation
The brain receives feedback from the body about the status of fuel stores. It integrates this with input from the external world as well as emotional state. From this information collage emerges energy expenditure and feeding behavior.
The Endocrine System
The endocrine system comprises a group of specialized organs and body tissues that produce, store, and secrete hormones. Endocrine organs are sometimes called ductless glands because their secretions are released directly into the bloodstream.
Endocrine system hormones regulate metabolism, body growth, and development; control the function of various tissues; and support reproductive functions, including pregnancy.
The primary glands of the human endocrine system are the hypothalamus, pituitary, thyroid, parathyroid, adrenal, pineal, and the reproductive glands: the ovary and testis. The pancreas – associated with the digestive system – is also considered part of the endocrine system.
Hypothalamus
A pearl-sized region in the human brain, the hypothalamus is the brain’s control center for energy balance. The hypothalamus regulates body temperature, thirst, hunger, fatigue, sleep, circadian cycles, hormone production, and sexual behavior. The hypothalamus is the central clearinghouse for many functions connected to the autonomic nervous system.
The hypothalamus links the rest of the body intelligence system to the endocrine system via the pituitary gland. A complex interchange of crosstalk within the hypothalamus results in decisions that give the pituitary gland its marching orders.
Pituitary
All vertebrates have a pituitary gland with similar functions, though structures vary.
The 0.5-gram, pea-sized pituitary is not part of the brain. It is a ductless gland that regulates many autonomic functions, including temperature, water balance, metabolism, blood pressure, pain relief, sex organ functioning, and growth. The hormones secreted by the pituitary gland stimulate and control almost all other endocrine glands in the body.
Thyroid
The thyroid gland comprises 2 connected lobes on either side of the neck. Almost all vertebrates have thyroid glands.
The thyroid modulates how quickly the body uses energy and produces proteins. The thyroid also moderates sensitivity to certain hormones. Thus, the thyroid is instrumental in controlling metabolism and growth.
Triiodothyronine and thyroxine are the principle thyroid hormones, synthesized by addition of iodine to the amino acid tyrosine. These hormones act on nearly every cell in the body: instrumental in metabolism, body temperature, heart rate, growth, and development.
Iodine is found in the ocean. It is a relatively rare element, and the heaviest essential element with biological function. Iodine deficiency leads to cognitive malfunction.
Tyrosine is an essential amino acid that cells use to synthesize proteins. Tyrosine is prominent in proteins that participate in extracellular signaling.
○○○
The parathyroid glands affect the amount of calcium in the blood and bones. Humans usually have 4 parathyroid glands, located on the back of the thyroid.
The adrenal glands sit at the top of the kidneys, dispensing hormones in response to stress.
The pancreas is a glandular organ that participates in the digestive and endocrine systems. As an endocrine gland, the pancreas produces several important hormones, including insulin, which regulates carbohydrate and fat metabolism. As a digestive organ, the pancreas facilitates digestion via the release of enzymes that help break down foodstuffs and absorb nutrients in the small intestine.
Muscle Memory
In a physically healthy human, muscles are 70–85% of body weight. Muscles are the body’s largest organ. Muscles work via calcium ions, the same as astrocytes.
Muscles are sense organs in a sense. We can feel our muscles, especially when they are out of sorts. This feedback is essential to gaining motor skills. Yet muscles themselves provide no conscious sensation, as Swiss physiologist Albrecht von Haller observed in 1757.
Peripheral nerve tissue is surrounded and supported by muscle tissue. For example, the sciatic nerve is the longest and widest single nerve fiber in the human body, supplying sensing for the leg and foot, both skin and muscle. It begins in the lower back, well in the grip of the deep rotators of the hip.
The trigeminal nerve, the largest of the cranial nerves, gives sensation and muscle control in the face and scalp. The brachial plexus provides innervation for the hands and arms. Both are enveloped by the neck muscles. And so on, muscular nerve bundle by bundle.
This juxtaposing of muscle and nerve forms a functional interdependency. The muscles are given feeling while the nerves are fed. Peripheral nerves rely upon surrounding tissues for nourishment and waste removal, like astrocytes manage brain neurons.
Disused, flaccid muscles don’t provide enough pumping action for intercellular fluids which are essential to proper feeding and bathing of nerve cells. The circulation of fluids within the long axon tubes is critical to the health of nerves’ membranes and propagation of action potentials. Inadequate pumping action of surrounding muscles reduces this hydraulic flow.
Chronically tense muscles are worse. Not only is fluid circulation for nerve cells curtailed, but the capillaries that supply nutrition and carry off waste are squeezed by constricted muscles. At the same time, these contracted muscles demand more nutrients and produce more waste. Toxins build and oxygen supply lessens, irritating nerves, which contributes to further tension in a dynamic feedback loop.
Chronically high pressure on nerve trunks from tight muscles impairs nerve electrical conductivity. 5 pounds of pressure on a nerve for 5 minutes can reduces transmission efficiency as much as 40%.
A capillary is delicate, with walls only a single cell thick. Once chronically constricted muscles squeeze a capillary so hard to crush it the capillary becomes a corpuscular corpse: replaced by scar tissue, with local circulation permanently impaired.
The results of such pressures, depending upon the muscles and nerves affected, can be numbness, tingling, spasms, pains, and headaches. Since nerve functioning to internal organs can be similarly afflicted. Dysfunctions propagate.
Such organ dysfunctions can have symptoms but are next to impossible to diagnosis because no local disease is apparent: at least for a while. Complications following in the wake of chronic muscular contraction can become grave. Areas in the body with interrupted flow stagnate like a brackish swamp, creating septic situations ripe for discomfort, decay, and disease.
This is a sorry sort of muscle memory. Regular exercise is preventative, and regular massage can be curative to some degree.
◊ ◊ ◊
Motor skills are the output of muscle memory, of which glia are the keepers. Astrocytes store the patterns that make for motor skills, while the nerves serve as communication conduits.
Strength training is exemplary. Strength increases well before muscle hypertrophy (muscle mass growth) and decreases in strength from detraining precede muscle atrophy.
Strength training begins with astrocyte growth coupled to synaptogenesis (synaptic growth) and enhanced motor neuron responsiveness. In other words, strength is first gained, or lost, by enhanced muscle memory and communication – mind before matter.
◊ ◊ ◊
Fine motor skills are of transitive movements, often done using tools as simple as a toothbrush. Muscle memory of fine motor skills is subject to disruption via task interference.
For example, in learning a 2nd finger pattern 6 hours after learning the 1st, the 1st is retained. But if the 2 patterns are learned back to back, the initial one is much more easily forgotten.
Dance classes capitalize on this muscle memory limitation by teaching several patterns in a single lesson, thus maximizing the learning curve and necessitating more dance lessons. Understanding how fine muscle memory works assists a dance instructor’s fine motor skills in lightening pupils’ pocketbooks.
Puzzle cubes involve a combination of algorithmic and muscle memory. Memorization corresponding to cube moves is incredibly difficult, but an advanced cuber learns efficiently with muscle memory riding shotgun on algorithmic repetition.
The finest of fine motor skills, especially the fingering required to master musical instruments such the piano, or the coordination between mouth and fingers in wind instruments such as the clarinet, weave learning patterns across multiple mind-brain regions which become interconnected.
There are functional differences between the mind-brains of professional musicians and their fans. These adaptations reflect early exposure to musical training and many years of practice.
A pianist hearing a learned musical piece can trigger involuntary synonymous fingering. There is a coupling between music perception and motor activity in trained musicians. Hence the ability of tight bands to jam with interlocking synchronicity through anticipation and minimal signaling of variation: there is mental room to focus attention on the artistic aspect of performance without needing to consciously control fine motor actions.
◊ ◊ ◊
The cerebellum is the physiological home base for motor learning. It is a primitive brain portion, similar across all vertebrates, including fish, birds, reptiles, and mammals, but there is considerable variation in size, shape, and development sophistication among these various creatures. Cephalopods with well-developed brains, such as octopi, have an analogous brain structure.
Basal Ganglia
Common to all vertebrate, the basal ganglia sits at the base of the forebrain (cerebrum). Strongly connected and functionally interdependent with the cerebral cortex, thalamus, and other brain areas, the basal ganglia are instrumental in a variety of functions, including voluntary motor control, muscle memory, parafunctional habits such as bruxism (grinding teeth), eye movements, and cognitive and emotional functions.
Basal ganglia are implicated in action selection as well as inhibition. Basal ganglia are central to motivation. Behavioral choices coordinated via the basal ganglia are influenced by input from many parts of the mind-brain, including the prefrontal cortex, a key player in executive functions in the cognitive system.
The basal ganglia are active in songbirds while learning songs. The firing rates of basal ganglia neurons in singing birds reaches 700 spikes per second: extremely fast. Basal ganglia circuits similar to songbirds are in the human brain.
Numerous disorders are associated with dysfunctional basal ganglia, including stuttering, attention-deficit hyperactivity disorder, athymhormia, obsessive-compulsive and other anxiety disorders, Tourette’s, and cerebral palsy.
○○○
Muscle memory is also referred to as procedural memory: remembering skills. Declarative memory is long-term recall of facts (semantic memory), events (episodic memory), and spatial maps (topological memory).
Procedural memory and declarative memory process similarly. First comes an encoding stage: the pattern situating into astrocytes, a somewhat fragile process susceptible to inaccuracies.
Encoding is strengthened by concentration. Eyewitness reports of crime scenes are often unreliable because attention is oftentimes not well focused on critical events, and so the initial encoding is patchy and subject to suggestion when prompted for later recall.
The 2nd stage of memory formation, dependent upon the quality of the 1st, is long-term memory consolidation.
The pathways and brain sites most important to muscle memory are distinct from declarative memory. The medial temporal lobe and hippocampus are notably active during establishing declarative memory.
Muscle memory is commonly acquired by practiced movement, but careful observation of a skill being practiced by someone else can result in muscle memory. Such social learning is exemplary of mind-brain integration.
Some muscle memory is hardwired. Facial expressions, once thought entirely learned, are at least partly inherited. Those blind from infancy possess numerous facial expressions.
American psychologist Edward Thorndike was a pioneer in the modern study of muscle memory: early in recognizing that learning can occur without conscious awareness. Thorndike studied the longevity of muscle memory, which explains why such skills as riding a bicycle are readily performed even if rusty from disuse.
Sensorimotor interplay – perception and movement – intertwines while learning any new skill. Children who have poor sensation in their lips and mouths cannot learn to talk normally, no matter the training.
Muscle memory is a functional skill, but the muscle tissues are also self-definitional. The mind-body intelligence system communing with the muscles creates a kinesthetic sense, defining a physical self-image. By contrast, extended lack of movement and sensation while in the conscious state induces hallucinations from disassociation, as the phantasmagoria of imagination struggles to fill the gap of sensory deprivation.
Kinesthetic and muscle memory are interdependent in providing a sense of normalcy: the mental feeling of “rightness.” Once a sense of normalcy is established for a way of doing something, perceived inefficiency or even pain does not alter behavior that feels right, unless repeated exercise results in modification: a relearning of rightness.
Muscle memory can be overcome, albeit not always for the better. Despite practice, muscle memory gives way to attitude. Athletes know that – whatever the game – it is a mental game. Muscle memory mixes with the confidence factor to determine performance. Muscle memory turns to mush with lack of self-confidence.
Old habits die hard. The feeling of rightness can be a formula for obstruction to achieving improvement.
The ease or difficulty of changing behaviors reflects the inner holistic: the mental rigidity that keeps the body locked on an unchanging track springs from a mind unwilling to absorb new facts and adopt new viewpoints. Spontaneity or rigidity is a way of being for one’s entire ecology.
The Brain Through Life
The human brain goes through 5 life stages: 1) conception to birth (0–10 months); 2) infancy into childhood (birth–6 years); 3) youngster through teenager (7–22 years); 4) adult (23–65 years); 5) aging (65 years onwards).
Into the World
Differentiation of the nervous system and brain in a fetus begins at about 3 weeks. In the 4th week, the brain is a tiny bulb at the end of a neural tube. By the 8th week the main sections of the brain have formed.
A newborn has as many neurons as an adult, but the number of glial cells continues to grow.
The brain begins to create sensory maps at birth based upon the new world it has entered. Like the subtle energy variations in an early universe, these initial brain pathways can shape lasting proclivities.
Infancy into Childhood
The brain at birth is 25% of its adult weight. Brain weight more than doubles in the 1st year.
Most brain growth occurs within the first 2 years from proliferating glia. The brain attains 90% of its adult size by age 6.
Imprinting
Evil, by definition, is that which endangers the good, and the good is what we perceive as a value. ~ Konrad Lorenz
Austrian zoologist Konrad Lorenz was a Nobel-prize-winning Nazi. The award was for his work in ethology: the study of the development of human ethos (human moral nature). Ironies never cease.
Messing with the minds of geese, Lorenz rediscovered imprinting: the instinctual association made by newborn animals that leads to parental bonding. Lorenz deceived goslings to bond to him and follow him around rather than their mother. In the repeated process of confounding baby geese into goose-stepping to his will, Lorenz learned that imprinting was strongest in goslings from 15 hours to 3 days after birth.
The concept of imprinting echoed to the perceptive Austrian neurologist Sigmund Freud, who observed, without resort to ruining other animals’ lives, that humans go through development stages in brief windows of time, and that these periods were formative: shaping individuals for the rest of their lives.
○○○
When a particular brain region that is thought to be essential for a function is lost, other brain regions suddenly are freed to take on the task. ~ American psychologist Michael Fanselow
From birth the mind-brain develops its capacity for perception, voluntary movement, and reasoning. The frontal lobes are especially active during developing the facility for emotional attachments, working memory, and planning. At 5 months babies can perceive facial emotions: a crucial survival skill.
The human brain develops slowly compared with other creatures. The earliest long-term memories form around 3 years of age. Before that the dramatic growth of new neurons disrupts long-term memory formation. Also, the physical instrument for long-term memory – the hippocampus – is still maturing. Long-term memory improves at ~10 years of age, as hippocampal growth slows.
Youngsters are more likely to recall an event if asked about it. This affects when long-term memories begin to reside.
The childhood memories of the Māori of New Zealand typically begin to stick a year earlier than they do for North American children. Among the Māori memories are honored and much discussed. A sense of self (self-awareness) is usually achieved by age 4 among Māori children.
The brain is most adaptive – a literal information sponge – during the formative period from infancy into childhood. This statement seems to conflict with the fact that infant memories are ephemeral: which they are, because the hippocampus is still maturing. The issue is not retention, but patterning.
In infancy, the brain is learning how to learn. What is being learned, and its retention, are largely incidental. What is critical is that the developing brain is actively employed: that the patterns for learning are being established.
Neglect, abuse, or exposure to violence during early childhood can has lifelong consequences, as it affects the physical substrate of the brain. The amygdala and hippocampus are areas especially affected. The childhood brain needs positive stimulation.
High levels of physical activity in the first few years of life stimulates brain development, especially for boys. The language and math skills of the physically active are sharper in the first years of school.
Each processing system has optimal windows of time for learning: where the brain is especially plastic and sensitive, accommodative to rapid growth.
Language manipulation is the most powerful tool a human can possess for social interaction and provides a strong basis for cognitive clarity.
The facility for language is innate, but skill with languages must be acquired. The full formative period for language development begins before birth and lasts to between 8 years and puberty.
Brain structure is shaped by the languages learned early in life. Early musical training builds language skill.
After the critical period, the ability to learn a 2nd language is less easily achieved: the mind-brain has less language plasticity.
Accents are picked up during the language formative period and hard to unlearn afterwards. After the language fast-track window closes, 2nd languages are not even processed in the same way or even the same part of the brain as the native tongue.
Toddlers typically learn more quickly than adolescents because the number of connections among synapses is 50% greater in an immature brain than in the adult brain.
The brain consumes its peak energy at age 5. 2/3rds of body’s resting energy expenditure goes to the brain, and almost half altogether. Relative brain energy consumption declines with age.
Human children evolved a much slower rate of childhood growth compared to other mammals and primates in part because their brains required more energy to develop. ~ American anthropologist Christopher Kuzawa
By age 6 the brain has reached 95% its adult weight and is just past its peak energy consumption. Between the ages of 6 to 13 the brain goes through growth spurts that affect understanding language and spatial relationships, and provide intellectual and social skill development, such as the ability to read and make friends.
Adolescence
Glia are ascendant during adolescence. The brain begins pruning unused neurons. The volume of white matter (glia) grows 5% between age 10 and adulthood, while gray matter (nerve cells) peaks at age 11–12, then falls.
The adolescent brain is primed for learning. Doing so keeps cells alive; otherwise they are lost from disuse.
The prefrontal cortex is the last to mature. It is instrumental in the control of impulses, reasoning, planning, and rational decision-making.
With the brain undergoing significant changes, puberty is an especial time of irritable and irrational behaviors. A sense of reward satisfaction lingers in teenagers, limiting impulse control and leading to inappropriate behaviors by acting in a social context that has already past.
The fact that the reward is gone doesn’t matter. An adolescent will act as if the reward is still there. ~ American psychologist Shaun Vecera
Teenagers are prone to take risks without cognizance of potential consequences. This comes from a still developing mind-brain lacking matured capacity for sound judgment.
Amygdala
High childhood anxiety is associated with enlarged amygdala, and with increased connectivity between the amygdala and distributed brain systems involved in attention, emotion perception, and regulation. ~ Chinese American behavioral psychiatrist Shaozheng Qin et al
The amygdala is the brain’s emotive center, remembering emotionally charged events. It is also instrumental in relationships and sociality.
The amygdala is necessary for processes that involve updating representations of value. ~ American neurobiologists Sara Morrison & Daniel Salzman
All sensory information goes to the amygdala to create mental sensation. From that first impression emotively based valuation of experience is determined in the amygdala. This then factors into motivation for action.
The amygdala extensively interfaces with the prefrontal cortex: the mind-brain’s executive system control center at the front of the frontal lobe.
Human response to animals, either affine or fearful, is hardwired in the amygdala.
Juveniles largely rely upon the amygdala for decisions, as the prefrontal cortex is still developing.
Once the amygdala is over-reactive, people tend to behave in an anxious, over-reactive way to things they see as a potential threat. ~ American psychologist Luke Hyde
The amygdala’s importance cannot be overstated. It is well connected to other brain regions involved with sensation and cognition.
In association with the hypothalamus and thalamus, the amygdala is part of the limbic forebrain. From an evolutionary perspective, the limbic system is relatively primitive. All vertebrates have limbic systems which perform similar processing. The limbic system is particularly well developed in social species.
The human amygdala is enlarged compared to other primates. Our amygdala is responsive to emotive content expressed by the whites of the eyes (sclera), such as fear. Other primates have dark eyes, and so lack this communication conduit.
The amygdala matures during puberty. Its response to visual sexual stimuli differs between women and men.
Adulthood
The adult brain processes emotional information more in the frontal lobe than during teenage years, tempering urges with a measure of cognitive caution. This provides a better sense of subtle social signals that others give.
Emotions
Emotion is distributed across the brain. ~ American psychologist William Cunningham
Emotions enliven the amygdala and are especially compelling to children and adolescents. The adult mind-brain is better equipped to register emotions and appraise them before acting. Doing so is a matter of self-control.
Turning an emotive sensation into a cognitive matter by detachment activates the language processing areas of the mind-brain. Labeling an emotion reduces its impact. The amygdala attenuates.
○○○
The brain reaches its peak power at ~22 years. This lasts for 5 years. Physically it is downhill from there.
Last to mature and the first to go is executive control in the prefrontal and temporal cortices. Episodic recall starts to decline. Processing speed slows. Working memory stores less.
Experience compensates for lessened mental acuity. The brain is like an equity fund heading south: past performance is not a guarantee of future returns.
Hormone changes as the decades wear on take a toll on brain wattage. For men, decline of testosterone during middle age is gradual.
In contrast, the experience of menopause can be dramatic. Beyond the hot flashes, fatigue, libido loss, and moodiness are brain changes, exemplified by forgetfulness and constricted concentration.
Seasoning through continuous learning is the best hedge for a brain that is not as well-equipped as it once was. An engaged mind keeps the brain keen.
The Aging Brain
The longevity that humans now enjoy is recent, and one for which evolution has not fully equipped us. The most important organs of cognition – the mind-brain – inexorably decline, even in the healthiest person.
The brain at 80 weighs 10% less than at 20. Tissue loss between adolescence and old age is 20–30%. The areas responsible for higher cognitive functioning are most affected.
The aging brain is less tolerant of noise, as filtering meaningful signals becomes more demanding. The sensory clutter that stimulates young brains becomes insufferable.
The senses also suffer with age. Smell sensitivity is particularly prone to loss, and with it zest in taste. As food losses appeal it becomes less important.
The rate of the diminution in brain wattage is highly variable. Maintaining physical and mental fitness by regular exercise prolongs mental acumen and aids memory retention, as does keeping active socially.
One of the best exercises for maintaining mind-brain acuity is walking, as it exercises both the senses and sensation. Knowing this reminds that the brain is just an organ of the body. An out-of-shape physique spells an out-of-sorts brain.
Time with the mind-brain in repose is equally important. Resting the mind through meditation is a powerful form of rest. Getting enough sleep is crucial to health; something which too few do in industrialized countries, especially those with ambition.
Not stuffing the body is as important as exercise and rest are to keeping fit. Reducing caloric intake is significant in reducing the pace of aging, including the mind-brain.
As the brain ages, memories fade as astrocytes and attendant nerve cells are lost in critical areas such as the hippocampus. Decay in the myelin sheath that insulates and regulates neural communication is a common symptom of an aging intelligence system.
The Brain by Gender
Any difference in the structure or activation of male and female brains is indisputably biological. However, the assumption that such differences are also innate or
hardwired” is invalid, given all we’ve learned about the plasticity, or malleability of the brain. Simply put, experiences change our brains. ~ American neurobiologist Lise Eliot
The differences in anatomy between the sexes reach into the brain. There are ~100 gender distinctions in human brains. (Note that the gender generalizations that follow are exactly that: statistical typifications. Skill levels are always individual.)
Befitting the slight sexual dimorphism of humans, male brains are 10% larger than females: mostly to handle the greater musculature, not deeper thinking.
Female brains mature faster than those of males. Girls start talking before boys.
The myelination of cranial nerves is accomplished in female brains by the mid-teenage years. This process completes a year or 2 later in boys.
Myelin coating improves behavior regulation via glia taking control of nerve cells. Myelination exhibits a crucial role in inhibiting inappropriate behaviors and choosing actions to meet goals.
Generally, the halfway point of brain maturation is met in girls by age 11. Boys do not reach this point until 15.
Differences in the hypothalamus and amygdala emerge early in life. Women have a larger hypothalamus, affording better emotive memory. Meanwhile, men have a larger amygdala for faster stress response.
When stressed, males tend toward addressing the source: either fight-or-flight. In contrast, females turn to others for support.
Literacy does not come as easy for boys, who tend to have more problems learning to read, especially if socially disadvantaged or in large families.
The planum temporale – a cortical area involved with language fluency – is larger in women than men. The planum temporale is one of the most asymmetric regions in the brain. Its size in the left hemisphere – where language processing predominates – is up to 10 times larger than the right.
While males mostly process language in the left hemisphere, females have active verbal centers on both sides of the brain.
Women use more words when describing emotive experiences and show greater interest in sharing such. Men tend to briefly analyze emotional memories before moving on to a different task.
The female brain has greater blood flow in the cingulate gyrus, which lies just above the corpus callosum. The cingulate gyrus is involved in forming and processing emotions.
A discrepancy in empathy between genders emerges in infancy and persists throughout development, though the gap between adult women and men is greater than between girls and boys owing to cultural indoctrination. This consistency between the sexes suggests an innate basis for empathy in the mind-brain.
Men are better at tasks that involve imagining spatial relations, such as determining navigation paths. Males also have a decided edge in mathematical reasoning ability.
In social skills, perceptual speed, and fine motor skills, males are the weaker sex. Topping this cake is the fact that men have a lower pain threshold than women. In sum, women are smarter and tougher.
While sex-related mind-brain differences do matter, they do not fully explain behavioral divergences or cognitive abilities. Hormones play a large role, as does personality and life experience.
The straight gyrus is a narrow strip running along the midline on the undersurface of the frontal lobe. It appears involved in interpersonal awareness and social cognition.
Women generally a larger straight gyrus: by about 10%, which makes sense when considering that mothers are the primary parent. But the picture is more complex than that. Men or women with a more feminine personality have a larger straight gyrus than those that are more masculine. This indicates that hormones are influential.
Brain Baths & Droughts
Déjà vu comes from a calcium wave. New experiences provoke pattern recognition from similar situations. Piecemeal matches invoke a slight cognitive disruption: a blip reflective trance from inundated astrocytes on the fringe of previous patterns.
Biologically, pleasure takes the form of astrocyte baths. The converse is also true. Humans suffering from chronic depression have fewer cortical astrocytes, as do schizophrenics, and less-intelligent people generally.
Depression may involve a gyral dynamic from lack of stimulation: fewer calcium waves and fewer astrocytes. In contrast, during mania, the incidence of calcium waves may be like an ocean during a hurricane: too roiling, leading to euphoria and hyperactivity.
Lithium has been used to elevate mood: to treat depression and bipolar disorder. Biochemically, lithium is an ionic replacement for potassium and calcium. Robust calcium puffs to stir astrocyte waves are essential for healthy mental functioning.
Those who take lithium report more emotional stability, but also tend to feel “not themselves,” as life’s experiences seem somehow dull and muted. Lithium ions are an ersatz substitute for calcium.
Serotonin is a hormone and brain neurotransmitter that affects mood and social behaviors. Serotonin imbalance has been associated with depression and schizophrenia. Even crayfish get anxious when their serotonin level is not right.
Hallucinations are a common schizophrenic experience. Serotonin may stimulate astrocytes into calcium wave activation of sensory processing without any neural stimulation from the sensory organs. In other words, hallucination comes by serotonin-induced stimulation of astrocytes absent sensation.
Depression treatment commonly comprises ingesting serotonin reuptake inhibitors, to allow serotonin to have a longer-lasting effect. Neurologists hypothesize that this allows longer neuron exposure to serotonin to achieve its mood-altering effect. But astrocytes also perform serotonin reuptake. The effect may be to stimulate astrocyte receptors to release more calcium puffs in the pathways. Extra activation of astrocytes when their numbers are depleted may compensate somewhat.
Oxytocin
“Oxytocin is one of the neurochemical foundations of sociality in mammals. It enhances social motivation to approach and affiliate with close social partners, which constitutes the basis for the formation of any stable social bond and facilitates its maintenance over time.” ~ American zoologist Teresa Romero
Oxytocin is a peptide of 9 amino acids. The hormone oxytocin is found in all vertebrates and has more ancient evolutionary roots.
In mammals, oxytocin acts in the brain as a modulator. Oxytocin is produced in the hypothalamus and its secretion regulated there.
Oxytocin is released into the blood by the pituitary gland. Oxytocin and its chemical cousin, vasopressin, are the only known hormones released by the human pituitary gland to act at a distance. Vasopressin plays a key role in homeostasis: specifically, the regulation of water, glucose, and salts in the blood.
Brain structures involved with emotions and social behaviors have dense fields of oxytocin receptors. This includes the hypothalamus, the amygdala, the anterior cingulate cortex, and the nucleus accumbens.
The hypothalamus is highly connected with other brain structures and is instrumental in sexual behaviors.
The amygdala is active while forming and storing memories related to emotional events, and fear conditioning (learning to predict aversive events).
The anterior cingulate cortex participates in error and conflict detection, and thereby associated with decisions (go/no-go).
The nucleus accumbens is lively while experiencing emotions related to pleasure, reward, laughter, addiction, fear, aggression, and the placebo effect.
There is an oxytocin receptor gene (OXTR) which has 2 variants: A (adenine) and G (guanine). People with the A variant tend toward increased sensitivity to stress, lower self-esteem, and are more depression prone. This is merely one observation that behavior and biology are intertwined. But OXTR is not destiny. And OXTR interacts with other genes as part of psychological makeup and dynamics.
Released into the bloodstream, oxytocin influences various organs, including the uterus and mammary glands.
Historically, oxytocin has been understood for its role in females, related to reproduction and maternal behaviors. Oxytocin is released in copious amounts for inducing labor, and after excitation of the nipples: stimulating milk flow for breastfeeding in nursing mothers.
Oxytocin is a chemical ingredient active in a broader expanse of behaviors, including orgasm, pair bonding, and anxiety. Oxytocin has been popularized as the “love hormone” for its profound effect on affection.
Oxytocin has various influences. Oxytocin increases with stress. Oxytocin chemically inspires trust and generosity, and reduces fear, thus affecting judgment.
Oxytocin likely affects other social emotions, including promoting envy and schadenfeude (pleasure from someone else’s misfortune). Oxytocin stimulates emotive empathy and sexual arousal in both males and females.
Elevated oxytocin impairs retrieval of unhappy memories and negatively affects learning. Animal studies indicate that oxytocin inhibits developing a tolerance to various addictive drugs (alcohol, cocaine, and opiates), and reduces withdrawal symptoms.
Autistic children have significantly low levels of oxytocin.
Psychoactive Substances
“What a long, strange trip it’s been.” ~ American musical group The Grateful Dead in the song “Truckin'” (1970)
Humans have a decided fondness for mind-altering substances. Contrary to the indication of Grateful Dead posters, a bear won’t eat a psychedelic mushroom, as it cannot bear the disorientation.
Psychotropic drug use affects glia. Any chemical compound that registers with the brain affects glia, and so is psychotropic to some degree.
Nicotine acts on the acetylcholine receptor, caffeine on the adenosine receptor. Both receptors are expressed in glia. Glia have receptors matching those of neurons, but it is glia, not neurons, that make sense of the world as part of the mind-brain.
Tetrahydrocannabinol (THC), the psychoactive ingredient of cannabis, mimics endocannabinoid neurotransmitters, inciting release of internal stores of calcium in astrocytes, causing calcium waves that psychically massage into a dreamlike state.
Ingested alcohol affects calcium-binding proteins, cause astrocyte calcium release. Alcohol also causes reactive oxygen species release, the same apoptotic kiss of cell death used to fight infections, which explains why alcohol is an antiseptic. Apoptotic kisses to astrocytes are a hoary practice of the Collective to stay stupid in pursuit of pleasure.
Opioids affect a variety of receptors throughout the brain: with the hippocampus, amygdala, and claustrum figuring prominently. Opioid receptors are ancient in evolutionary terms. They were already present with the origin of jawed vertebrates over 450 million years ago. This explains both broad receptivity and the highly addictive nature of opium.
Usually, habitual use of psychoactive agents represses the natural cellular dynamics of receptor production via artificial supply. Near-constant induced receptor activity causes a cell to manufacture less of the receptor; hence addition by feeling a deficit when the unnatural supply is withdrawn.
Cocaine owes its addictiveness to merrily stimulating reward pathways by inhibiting serotonin, norepinephrine, and dopamine reuptake. The mood elevation that cocaine yields by allowing these neurotransmitters to slosh around for too long gives way to irritability and depression when drug use is stopped.
When the artificial stimulation of neurotransmitters is withdrawn, cell signaling is diminished. Withdrawal symptoms nag until natural receptor production can recover.
○○○
The psychological desire for stimulation leads to a dynamic of physiological change if that desire is habitually satisfied. Astrocytes, which are center stage for all our cognitive events, are cells that habituate to stimulus patterns. Desire defines as a feedback gyre.
Patterns
The mind acts as a pattern matcher, using archetypes and extrapolation. This is why it is easier to learn material tangential to that known than entirely new subject matter. Familiarity invokes mental paths already blazed.
Pattern recognition commonly transpires on key features. Much goes unnoticed in object recognition.
Dragonflies have been known to try laying eggs on hood of a shiny metal car, mistaking the sheen for that of water: key feature confusion.
Turkey hens breeding for the first time will accept as chicks any object that makes the recognizable cheeping call. Deaf turkey hens kill most of their chicks, not having received the auditory sign-stimulus for parental behavior.
Male mosquitoes respond with high selectivity to the sound of female mosquito wings, which beat at a characteristic frequency with differs slightly from their own. Mosquito males can be attracted to a tuning fork of the correct frequency.
These false positives of key features explain why mimicry works. Adaptation equips mimics with the key features to copy while ignoring ancillary features that lack import.
Recognition failure cannot all be explained by gaffes in perception. Sometimes the senses themselves miss the cue, as the senses themselves are attuned to important stimuli.
Male green tree frogs croak with 2 peaks of sound energy: a low at 900 Hz and a high at 3,000 Hz. Female frog ears are attuned to those frequencies. Conversely, males are attuned to the different sonic signature of females. The hearing of each sex is keyed to different frequencies.
This is exemplary of efficiency adaptations specific to speciation. Signal-to-noise is enhanced, and energy consumption reduced, by having the senses limited to and most acute at the ranges where relevant information lies. Unsurprisingly, human hearing is keenest in the range of the human voice.
Such sensory and mind-brain adaptations may come through coevolution. For example, plants show helpful signature patterns to pollinators in the light frequency range to which the pollinators’ vision are most responsive. (How plants have this intimate intelligence to adapt to is a mystery.)
There is something attractive in the outsized. The larger an egg is, the more it stimulates incubation in a bird. Lipstick renders a woman’s lips supernormal, and the woman comelier. Exaggerated response to uncanny stimuli is an inevitable outcome of recognition systems focused on key features.
Supernormal stimulation is exceedingly common in mating displays. Females generally prefer supernormal males as a suggestion of good genes and vice versa. Peacocks are a classic example, but there are many others, including men’s preference for women with ample bosoms, as a presumed tell of a female’s ability to nurture offspring. Biological bias beckons for what is commonly called “taste.”
Meditation & the Brain
There are 4 nominal states of consciousness: waking, napping (asleep), dreaming, and transcendence. All these states have levels of depth or intensity which can blur boundaries between states. The mind may be in more than 1 state of consciousness simultaneously.
Together these states form a 4-way Boolean logic table of mind-body modes. In only 1 state, while awake, is the system fully activated. The other 3 states are different forms of rest.
While awake, the mind-body is active. Asleep is the ultimate downtime, where the mind-body is in repose. During dreaming, the mind is actively processing memories and fabricating phantasms, but the body remains at rest.
In achieving transcendence the mind is silent while the body is resting but receptive to stimuli. The transcendental state is a deep form of rest: more profound in refreshing the mind-brain than equivalent time asleep. This owes to strengthened connection of individual consciousness with the universal field of Ĉonsciousness.
A key property of conscious sensations is their inherent integration. Perception is not of isolated percepts but a single, unified experience, albeit where aspects may be ascertained in the mind in isolation. At the physical level, such unification requires a cooperative activity. The insula and claustrum are instrumental in delivering the experience of consciousness as an integrated experience.
Meditation alters the brain. Long-term meditators have a thicker insula. As the claustrum adapts its pathways to the various information regularly received, the claustrum is instrumental in ensconcing the long-term effect of meditation.
Learning is characterized by synchrony between distinct brain areas. The practice of meditation improves the ease by which such harmony is achieved.
The biological changes from meditation practice stimulate the actualization of human potential. Meditation holistically raises awareness of everything.
There are 3 states of consciousness beyond the 4 everyone experiences (transcendence occasionally occurs to everyone as a momentary peaceful repose). In enlightenment, transcendence is sustained while awake. A quiet mind enhances perspicuity and calm, as well as entraining waves of bliss from enhanced connectivity with Ĉonsciousness.
A sense of dynamic connectedness is apparent to someone in coherence consciousness. In unity consciousness (aka realization), the unity of Nature is directly appreciated. In realization one exists in the fullness which life offers.
Insula
The insula is a structure deep in the cerebral cortex, involved with consciousness. It has a diversity of functions relating to self-awareness, cognitive processing, interpersonal relationships, emotion, and regulation of the body’s homeostasis. The insula facilitates interoceptive awareness of the body’s states, such as the ability to regulate one’s own heartbeat.
Related to social experiences, the insula is active in processing moral attitudes (mores), empathy, and orgasms. The insula is involved in the sensation of pain, particularly the empathic experience of pain: feeling pain by perception outside oneself, not just internal bodily stimulation of pain by injury.
The Pain of Altruism
Pain functions to alert an animal to potential damage and to reduce activity after trauma. Pain may also motivate social activity. In certain circumstances, the presence of others can affect the intensity of pain.
Across all human cultures, women receive help in birthing. In contrast, solitary birth is the norm for other primates.
The source of human labor pain comes from the contraction of the uterus and dilation of the cervix. This pain signals a risky and potentially lethal event hours later: birth. The delay between the onset of pain and delivery affords opportunity to enlist assistance.
Childbirth for women is uniquely painful. This owes to a size mismatch between a baby’s outsized head and its mother’s pelvis.
Women are not the only primates at risk when birthing. Marmosets have similar head-to-pelvis disproportionality and birth-related mortality. Yet marmosets and other mammals give birth rather painlessly. Ungulates birth large, long-limbed offspring with substantial chance of complications but little evident distress.
As other animals must often carry on by themselves, putting them in pain to deliver offspring would be insensible, whereas with women pain provokes altruism and social bonding at a critical period of life for both mother and child.
Claustrum
Waves of information travel within the claustrum. ~ English molecular biologist Francis Crick & American biologist Christof Koch
The claustrum is a thin, irregular sheet of gray matter layered through white matter near the insula: by volume 0.0025% of the brain. All mammals have a claustrum.
The claustrum receives input from almost all regions of the cortex and projects back to almost all regions of the cortex. The claustrum is the communication conduit of mental integration from the white matter that surrounds it.
Brain Damage
The mind-brain exhibits self-organized criticality. For good or ill, early activity patterns become embedded.
With somewhat malleable compensation for physical damage owing to limited redundancy, the brain has a certain robustness. People who exercise their mind-brain by learning and problem-solving throughout life may have their brains ravaged by Alzheimer’s disease, yet retain a goodly portion of their memories and mental facilities.
Conversely, the brain is fragile. By altering epigenetic dynamics which never revert to healthier functioning, early traumas can have lifelong effect. For example, altered amygdala activity in early life may result in pathological aggression in adulthood.
